1. Field of the Invention
The invention relates to a method of displaying multiple points of interest on a personal navigation device, and more particularly, to a method for spreading out closely located points of interest to create a flower shape surrounding a selected position.
2. Description of the Prior Art
Global Positioning System (GPS) based navigation devices are well known and are widely employed as in-car navigation devices. Common functions of a navigation device include providing a map database for generating navigation instructions that are then shown on a display of the navigation device. These navigation devices are often mounted on or in the dashboard of a vehicle using a suction mount or other mounting means.
The term “navigation device” refers to a device that enables a user to navigate to a pre-defined destination. The device may have an internal system for receiving location data, such as a GPS receiver, or may merely be connectable to a receiver that can receive location data. The device may compute a route itself, or communicate with a remote server that computes the route and provides navigation information to the device, or a hybrid device in which the device itself and a remote server both play a role in the route computation process. Personal GPS navigation devices are not permanently integrated into a vehicle but instead are devices that can readily be mounted in or otherwise used inside a vehicle. Generally (but not necessarily), they are fully self-contained—i.e. include an internal GPS antenna, navigation software and maps and can hence plot and display a route to be taken.
One useful feature of personal navigation devices is the ability to list nearby points of interest. In rural areas, points of interest may be spread out far from each other, and can easily be shown on the display of the personal navigation device. However, when traveling through cities or other areas where there are many points of interest in close proximity to one another, there can be tens of points of interest located very close together. It is difficult to clearly show multiple points of interest that are in very close proximity to each other on the display of a personal navigation device. To deal with this problem, the prior art has used several different approaches for presenting information about points of interest to users of personal navigation devices.
One method used in the prior art is assigning different priority levels to different types of points of interest. For instance, an office building can be given a low priority while a hospital or a tourist attraction can be given higher priority. Once the priority levels have been established, the personal navigation device can be set to only display points of interest having a priority level equal or greater than a minimum priority. Otherwise, if there are still many points of interest meeting the minimum priority level, the personal navigation device will display only the points of interest with the greatest priority level.
One problem with the traditional approach to displaying points of interest is that if several points of interest occur at the same location or nearby locations, only one type of point of interest icon is drawn, which will be the icon representing the point of interest having the highest priority level. Another related problem is if a point of interest has been selected as a target destination for a user's trip, it is still not shown on the map if this type of point of interest was not enabled or not given high enough priority.
In addition, it is not often possible for users to narrow down categories to a finer granularity of point of interest types, such as selecting curry houses within the restaurant category, or selecting specific chains such as Starbucks™ within the coffee shop category.
Other problems come when the areas displayed on the map change when a user continues driving. As the map point of view changes, points of interest will appear and disappear from the map as their relative positions and priorities vary over time. Having icons constantly appear and disappear can be distracting to users.
Many personal navigation device manufacturers include more points of interest on a map than necessary for the average user because they want the user to appreciate all of the points of interest that the personal navigation device displays. However, most of the time, users are not interested in many of these points of interest. For example, restaurants, Automated Teller Machines (ATMs), etc. are only of interest when you need them, and are not required for every day driving.
After points of interest are displayed on the map, the user may find out more information about one of the points of interest by selecting it. However, if the point of interest that they are interested in is not shown as one of the displayed types of points of interest, they do not have this option. Instead, they may need to zoom in and move the map around in order to display the point of interest that they know is enabled. This may cause confusion as to why they are not able to find the specific point of interest on the map when they know that the point of interest is actually there.
Another problem comes when the user touches a map at a specific location containing multiple points of interest. In this case, the personal navigation device cannot tell which point of interest the user is interested in, and cannot show them the correct location details.